Electrical heater



y 3, 1951 c. c. DOYLE 2,559,410

ELECTRICAL HEATER Original Filed Feb. 15, 1945 KZ 2 5 /6 w 21 2 2 42 -19 S 24 5 74, Q 15 1 a 1; 15 57 56 28a. 40 j? 4 28 INVENTOR.

ATTK

Patented July 3, 1951 ELECTRICAL HEATER Charles C. Doyle, Willoughby, Ohio Original application February 15, 1945, Serial No. 578,102. Divided and this application October 12, 1949, Serial No. 120,832

1 Claim.

This invention pertains to the structure of a long marketed electrical-resistance heater and constitutes subject matter originally claimed in, but divided-out from, my parent application entitled Electric (infrared) Heating Appliance, filed February 15, 1945. Serial Number 578,102 now Patent Number 2,495,513.

The objects of the new reclaimed origination were and are 1. Provision of a structure comprising a reflecting hood possessing advantages of efliciency, sturdiness and facility both of assemblage and of mounting wherever its heating or drying function is desirable.

2. Plural adjustability of the reflector and resistance unit assembly.

3. Gang arrangement of the resistance 'units (nichrome wire coils as illustrated) together with a controlwhereby varying combinations thereof may be energized.

4. Dual-function flanging in the reflector assembly.

5. Interpositioning between a control switch and reflector-carried studs of a dielectric post which is operatively connected with the switch by wiring adapted to enter the latter and also connected, in lieu of wiring, by bars suitable for high voltage.

6. Use of a heating unit of infrared glow zone which is not enclosed like an oven, whereby improvedly to achieve an oxidizing depth of heat penetration without hazard of charring or burning under proper control.

Adverting to the drawings Figure l is a perspective view, from above, With certain parts of the heating unit omitted and one part partially cut away.

Figure 2 is a bottom, plan view of the open side of a reflector showing a gang arrangement of electrical resistance elements therein.

Figure 3 is an elevation of the left end of Figure 1.

Figure 4 is a vertical. longitudinal section through a pair of segmental end walls and connecting a reflector and a surmounted hood, to reveal enclosed parts in elevation.

For convertible adaptation to employment with differing kinds of machines so that the most effective positioning of the source of infrared heat may be accomplished, the multi-adjustment of the heater is advantageously incorporated. As shown, a supporting tube I is L-shaped to comprise a horizontally extending arm. A housing 2 comprises end walls 3 and 4 of segmental shape to include upper, arcuate-edge-defining portions 5 and 6 respectively. Opposed sides of the walls 3 and 4 are provided with correspondingly arcuate flanges I and 8 respectively which serve not only as stiffening ribs, but as ledges to support the arcuate end edges of a concavo-convex reflector 9 which is provided with a pilot light window or windows I 0 which latter appear clearly to view in Figure 1. Screws II serve to secure the reflector to the flanges "I and 8. As exemplified, the median, longitudinal section line of the reflector is provided with live equispaced holes I2. The portions 5 and 6 are provided with holes 50, and "la in which is journalled a tube I3 which is in telescopic connection with the horizontal arm of the tube I and which has its outer end intersected by a cotter pin I4 to prevent its withdrawal through the hole 60.. The connection just described permits of two dilfering adjustments of the heating unit-a horizontally slidable adjustment on the tube I and a swingable or turnable adjustment about the tube I. A set screw I3a passing through a lug 6b fixes the heater in any desired tilted position by engagement with the tube I.

As portrayed, an alined gang of four electrical resistance units are to be suspension-carried within the metallic reflector 9 and, for effecting a reflector-insulated connection therebetween, five terminal posts of peculiarly-composite construction are shown in Figure 4. Because duplicates, the singular number will be used in describing the assembled elements of such terminal connectors or posts, as may be observed in Figure 4.

A stud I5 has a diametrically reduced and threaded intermediate section It inserted upwardly through the hole l2 in the reflector, such hole being considerably larger in diameter than the section I5. Interposed between the studs shoulder and the lower surface of the reflector is a dielectric (mica) washer I I and snugly fitted between the section I6 and the annular margin of the hole I2 is a dielectric (mica) washer I8 of substantially the same thickness as the thickness of the reflector at its hole margin. The dual purpose of the washer I8 is insulation of the section I5 from the reflector while holding the stud against radial displacement after a clamping action has been effected in cooperation of an upper dielectric washer IS, a superimposed metal washer 20 and a nut 2|.

It is to be understood that my infrared heating units are sometimes employed in an inverted position or with the concave side of the reflector facing upwardly instead of downwardly. Connection with a source of electric current is had through a cord 22 (see Figure 1) which entering through the wall 5 becomes attached to the nearest post, other connecting wires 23, 24, 25, 26, and 21 progressively leading to the other four posts and to a three-heat switch 28 carrying a pilot lamp 28a and appropriately carried by the outer side of the wall 3, and additional wires 29 and 30 (also passed through suitably located holes in the wall 6) connecting the switch with a pair of the posts in a manner dependent upon which grouping of simultaneous or stage energization of resistance units, carried one between each pair of adjacent ones of the posts, has selectively determined.

When applied to printing presses on which paper stock of varying width is conveyed, the switch one of the resistance-wiring units.

control is perhaps preferably such that three grades of heat, low, high and medium may be delivered by the two end pairs. it is preferred to effect the medium or even the low stage of heat by energization to an infrared glow, but by restriction of any energization to the chosen number of resistance units less than the total number in the gang arrangement which is, of course, not necessarily along a straight line as exemplified in the drawings and as is more commonly adopted.

Since no claim is confined to any of the specific wiring diagrams which are feasible within the experience of any electrician and which are applicable to the switch and multi-post connections on the convex side of the reflector, th description of that part of my appliance may approvedly be terminated by adding that one of the wires, say, the middle-post-connected one 25 loops around a further reduced threaded section 3| of the stud to become clamped against the nut 2| by a smaller nut 32. A hood 3%, conforming to the arcuate edging of the wall sections 5 and 6, has longitudinal edge flanging resting on, and

secured by screws 93a to, the reflector 9, the

screws 83a passing through the latter and into tapped holes in the flanging l and 8.

The lower end of each steel stud has a tapped hole 24 for occupancy by a brass screw 35 having a head 36 adapted to engage a copper washer 31 whereby to bind one of the leads to an end of Not long after February 1945 when the parent application was filed, I commenced substitution for steel, copper and brass (furnishing bimetallic contacts, either between one metal and a different metal or between a metal and an alloy), employing more successfully stainless steel, nickel and Monel-the stud i5, screw 85 and washer 81 each being composed of one of the three identified improving substitutes.

Each resistance unit being like the others, only one need be described and consequently the singular number will again be employed. A cylindrical core or spool 89 is exteriorly or peripherally fashioned with a helical groove 18, sharply V- shaped in cross section advantageously to provide an air space at the bottom thereof through which air circulation eventuates, measureably to promote dissemination of heat and to prolong the life of the resistance wiring.

Consequent to the penetrating property of infrared heat as delivered by my resistance units, it is merely preferable also to have any energized coil glowing at full or maximum temperature, any resultant high, low or medium heat zone being accomplished by selectively varying the number'of coils which are energized subject to the chosen wiring diagram and the switch control.

While a gang of four alined resistance-coil units is illustrated, large printing presses of the web or winding and unwinding-roll type would require a multiple of that number of unit coils. Besides its ornamenting function as a dome, the hood 38 supplies a stiifening function to the reflector and has the second, utilitarian function of lessening heat loss in a direction from the concave toward the convex side of the reflector. On high-voltage installations, it is desirable at times to use bus bars (heavy copper or some conducting alloy) as connectors between those ends of the studs 15 which are within the confines of the hood 33 and convex side of the reflector. However, because such bars are not directly connectable with standard switches, in those instances More often,

(lava, for example) with which both the bars and the flexible wiring from the switch are connected.

In other cases it has been found desirable to insert a heat-resistant (asbestos) between the switch and that end wall to which the switch is attached. The means for fixing the heating unit in any chosen position of swinging adjustment about the tube 1 as an axis, may, instead of the set-screw 13a, consist of projecting stop on the end wall for alternate engagement, for instance, with an edge of the bracket 54. Such a substitute manner of fixing the swinging movement, not being claimed, requires no further mention.

To particularize or more specifically to describe the simultaneous energization of all of the row of resistance units or selectively different groups thereof, it is added that whether the wiring diagram is for volts A. C. or for 220 volts A. C. or D. C., the lead wires to the switch 28 from suitable combinations of the ends of the studs l5 which are on the convex side of the reflector HJ effect a hook-up whereby when the switch is set at low the pai of wire-wound spools at one end are energized, when the switch is set at med. only the other end pair of resistance units becomes energized and when the switch is turned to high all four of the resistance units are simultaneously energized. As will be readily understood by any skilled electrician, differing pairs of 'thereabove, a support journaled in upper portions of said end walls, a switch on one of said end Walls, wiring connecting some of said terminals on the convex side of said reflector with each other and with said switch whereby, subject to connection with a source of current, operation of said switch successively energizes different ones of said units and a cover for the wiring on the convex side of said reflector, said cover being fitted and secured to margins of the upper portions of said end walls.

CHARLES C. DOYLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,255,840 Ledig Feb. 5, 1918 1,539,734 Hauber May 26, 1925 1,837,000 Wertz Dec. 15, 1931 2,052,037 Sawin Aug. 25, 1936 2,229,828 Wach Jan. 28, 1941 2,333,683 Schuldiner Nov. 9, 1943 FOREIGN PATENTS Number Country Date 489,850 Great Britain Aug. 4, 1938 543,268 Great Britain Feb. 17, 1942 "592,724 Great Britain Sept. 26, 1947 

